1. Field of the Invention
The present invention relates generally to a signal measurement systems and, more particularly, to voice controlled signal measurement systems.
2. Related Art
Conventional signal measurement systems such as digital oscilloscopes sample, record and display time-varying analog signals. Samples of an input signal are taken and quantized, and the resultant digital representations are stored in a waveform memory under the control of a sampling clock. The acquired data may be subsequently read out as locations in memory are sequentially addressed by a clock signal to provide digital data that can be converted to a time-varying output signal for a waveform display. The sampling clock may be operated at one of several selectable rates depending upon the frequency content of the input signal. The selection of the portion of the analog input signal sampled and stored is determined by appropriate triggering circuitry to enable the operator to display the desired portion of the waveform.
Generally, as used herein the term “signal measurement system” includes any type of measurement system that receives and processes one or more signals. One common type of signal measurement system is test and measurement instruments, which broadly include analog and digital oscilloscopes, network analyzers, spectrum analyzers, logic analyzers, waveform recorders and the like.
A primary purpose of analog and digital oscilloscopes has been to sample signals generated by and between electronic components, circuits and sub-assemblies, referred to generally as the device under test, or DUT. With the advent of increasingly sophisticated DUTs, as well as a decrease in the size and a corresponding increase in the density of components included in DUTs, current probing needs, which generally require the simultaneous capturing of multiple signals, far exceed the capabilities of currently available oscilloscopes. This historic problem has become more pronounced since the introduction of surface-mount technology (SMT). SMT is currently the primary method by which electronic components are attached to printed circuit boards. Relative to its through-hole technology (THT) predecessor, SMT provides for the use of extremely small component packages and extremely high density interconnects between the components and the printed circuit board.
It is at times difficult and often impossible to probe such small components in such a high density interconnect environment using today's oscilloscopes. In most cases, probes can no longer be clipped to a component lead and left unattended while the operator operates the oscilloscope. Instead, operators must hold steadily with one hand one or more probes against the desired component leads, while operating the oscilloscope with the other hand. If this difficult task can be accomplished at all, the requisite diligence required to properly probe the DUT distracts significantly the operator's concentration on the oscilloscope and captured waveform data. Further, the inevitable intermittent contact between the probe and the component lead causing numerous probing errors. As a result, measurements are often performed repeatedly to insure accurate measurements are obtained. In addition, the probe often slips off of the lead during testing, coming into contact with multiple components or component leads, inadvertently and unknowingly shorting together two or more adjacent leads, damaging the system component being tested.
This has been a long-standing problem for oscilloscope operators, although it has become more pronounced in recent decades with the advent of SMT. Accordingly, a number of approaches have been developed over the years to overcome this recurrent problem of conventional oscilloscopes. For example, multiple operators are sometimes used to perform a single signal measurement operation. One operator would control the probe(s) while the other operator controlled the oscilloscope. The labor costs associated with performing such measurements increased accordingly.
Another approach has been to solder a lead to the component at which a measurement is desired. However, this approach is time consuming, exposes components to potential damage and often results in inaccurate measurements. In particular, when measuring high frequency signals, the addition of even the smallest solder and lead add a capacitance and/or inductance to the measured circuit, preventing accurate measurements.
A distantly related solution commonly found in many test environments has been some form of makeshift device to invoked oscilloscope operations. For example, solenoid driven arms activated by a simple foot switch have been used to advance an oscilloscope to the next measurement setting. However, at most such a makeshift approach are quite limited in operation, performing fixed measurement sequences characteristic of manufacturing environments. Such devices are ineffective in testing environments more commonly occurring in component and system design testing.
What is needed, therefore, is a mechanism that allows for the easy, single user operations of oscilloscopes and other signal measurement systems.